Conductive hydrogel containing 3-ionene

ABSTRACT

Cationic polyelectrolytes formed by the polymerization in absence of oxygen of a monomer of the general formula: dispersed   &lt;IMAGE&gt; where x is 3 or more than 6 and Z is I, Br or Cl to form high charge density linear polymers are dispered in a water-soluble polymer such as polyvinyl alcohol to form a conductive hydrogel.

ORIGIN OF THE INVENTION

The invention described herein was made in the performance of work undera NASA contract and is subject to the provisions of Section 305 of theNational Aeronautics and Space Act of 1958, Public Law 83-568 (72 Stat.435; 42 USC 2457).

CROSS REFERENCE TO RELATED APPLICATION

This application is a division of Ser. No. 280,649, filed Aug. 14, 1972,now Pat. No. 3,898,188.

BACKGROUND OF THE INVENTION

1. Field of the Invention:

This invention relates to novel polyelectrolytes. More particularly, theinvention relates to polyelectrolytes having a high concentration ofcationic nitrogen centers.

2. Description of the Prior Art:

Poly-quaternary ammonium polymeric polyelectrolytes have generally beenproduced by the copolymerization of a dihalide and a ditertiary amine.The more desirable short chain monomers should produce the highestcharge density polymers. However, many of the C₁ to C₆ combinations ofmonomers produce cyclic rather than linear polymeric products.

Polyammonium salts can also be formed by the homopolymerization of ABmonomers such as haloalkyl tertiary amines. In German Pat. No. 1,126,396which disclosed the synthesis of an AB monomer of this type, it wasnoted that the AB compound was unstable and whendimethylaminoethylchloride was heated to between 80° C. and 100° C. inwater, a viscous material was recovered identified as a polyammoniumsalt. However, it is now known that this compound forms a cyclic 6member ring.

Gibbs et al, (JACS 55, 753, 1933) polymerizeddimethylaminopropylchloride (DMAP Cl) or BR DMAP Br in bulk on a steambath. This procedure is only capable of forming low molecular weightproducts. The molecular weights were determined from the ratio ofnon-ionic to ionic halogen in the product. This method of determiningmolecular weight is now considered inaccurate and would provide highervalues than the analytical method utilized in the present invention.

High molecular weight polycationic materials having high charge densitywill find many uses such as flocculants in the clarification ofresidential and industrial water supplies, and effluents, as dewateringagents, as flotation agents, as catalyst and pigment retentionadditives, and as gelling agents. Polyelectrolyte materials will alsofind use in the rheological modification of fluids such as frictionreducers, as dispersants for clay and sludge in both aqueous and oilbased systems as well as antistatic agents, and additives to cosmetics,textile finishes and lubricating oils. These materials generally exhibitgermicidal action and are effective bactericidal and fungicidal agents.A further important area of application is in the preparation ofelectroconductive photocopy papers.

All of these applications are dependent on the quaternary ammoniumfunction and the availability and density of the groups. The activity inall cases will be enhanced by improving either or both of thesecharacteristics.

SUMMARY OF THE INVENTION

High charge density polymers having a molecular weight above 5000 areproduced in accordance with this invention by polymerization underoxygen excluding conditions of a monomer of the formula: ##STR2## wherex is 3 or more than 6 and Z is I, Cl, or Br.

At values of x other than 3 or 7-10 cyclic compounds are formed andlinear homopolymerization does not occur. Monomers such asdimethylaminoethylchloride or cycloalkyl, benzyl or phenyl substitutedamino alkyl halides as taught in German Pat. No. 1,126,396 do not formhomopolymers.

Furthermore, if the monomer of formula I is characterized as an ABmonomer where A is (CH₃)₂ N-- and B is Z then the homopolymer will havethe formula: ##STR3## where n is an integer of at least 200 and themolecular weight is preferably at least 30,000.

Thus the polymer is always terminated by A and B functional groups. Incontrast polyquaternary polymers prepared from A-A, B-B monomer mixtureswould form an unresolved mixture of A-A, B-B, and A-B terminatedpolymers.

Furthermore, in the A-A, B-B polymerization the stoichiometry must beexactly balanced or chain termination occurs. Highly polar solvents mustbe utilized and the high charge density present with monomers such asA(CH₂)₃ A and B(CH₂)₃ B also interferes with the production of highmolecular weight, linear chains. Furthermore, the mixed functionality ofthe terminated mixtures prevents formation of star and branched polymersin accordance with the invention.

The branch polymers have a comb-like structure and are formed byattaching a plurality of units of the homopolymer of the invention to apolymeric substrate containing a plurality of functional groups reactivewith either (CH₃)₂ N-- or Z-- of the AB monomer. The polymeric substratemay be selected from polymers having a repeating structure of theformulae: ##STR4## where R¹ is the residue of the polymerizationreaction forming the backbone of the polymer and may be aliphatic,aromatic, typically containing from 2 to 30 carbon atoms depending onthe spacing desired for the branches. R¹ can be hydrocarbon such asalkylene or heterocarbon such as polyether, polyester, polyurethane,excluding groups that react with A or B as defined above.

R² can be hydrogen, lower alkyl or aryl such as phenyl. R³ is a shortchain linking group such as lower alkylene, phenylene, alkyl ester andthe like. D is a functional group reactive with either A or B such asnitrogen. (R⁴)₂ N or Z where R⁴ is an organic group such as lower alkyl,aryl, aralkyl and n is an integer. In the case of Z, R³ should not bephenyl since the halogen is not sufficiently reactive with the tertiaryamine groups of the AB monomer.

Suitable polymeric substrates are polymers such as poly-4-vinylpyridine, polyethylene imine, polyvinylbenzylchloride,polyepichlorohydrin, polydimethylaminomethyl ethylene oxide,poly-dialkylaminoalkylacrylates such as poly-dimethylaminoethylacrylate, polyalkylaminoacrylamides such as polydimethylaminopropylacrylamide and the like. The polymer may be syndiotactic, isotactic, oratactic.

Star polymers having a molecular weight of at least 5,000 are formed byattaching radial sections of the homopolymer of this invention to acentral monomer of the formula: ##STR5## where Y is a central,polyvalent, comparatively low molecular weight organic group having avalence of 3+m, m is an integer from 0 to 3, R³ and D are as definedabove. Y can be an aromatic compound such as benzene or lower alkylatedbenzene. Suitable central monomeric compounds being2,4,6-tri-(chloromethyl)-mesitylene, 1,2,4-tri-(chloromethyl)-benzeneand 1,2,4,5-tetra-(chloromethy)benzene. The two benzene compounds areprepared from p-xylene in accordance with the procedure disclosed by M.Kulka, Canadian Journal of Research 23, 106 (1945). The central monomercan also be a polytertiary amine compound such as compounds of theformula: ##STR6## where p is an integer from 2 to 10 and R⁴ and R³ areas defined above.

The polymerization reaction in each case involves head-to-tailquaternization reaction of the A-B monomer to form linear chains. Inorder to obtain polymers having a molecular weight above 5,000 andpreferably from 30,000 to at least 60,000 the reaction must be conductedunder oxygen excluding conditions, suitably by deaerating or degassingthe reaction mixture before polymerization and by blanketing thereaction mixture with an inert gas, such as nitrogen or vacuum duringpolymerization. Preliminary deaeration can be effected by bubblingnitrogen through the reaction mixture for a minimum period or byapplying vacuum to the mixture for a sufficient period beforeapplication of heat. It has been found that carbon dioxide inhibits thequaternization reaction and oxygen causes the formation ofwater-insoluble products.

It is also desirable that the AB monomer be present in the reactionmixture in a relatively high concentration. The rate of reaction and themolecular weight are dependent on monomer concentration and temperature.The monomer concentration is preferably maintained at no less than 2molar and preferably 3-8 molar and the reaction temperature iscontrolled within 40° C. to 125° C., preferably 90° C. to 110° C.Completion of polymerization can be determined by monitoringdisapperance or consumption of monomer.

A preferred AB monomer from the viewpoint of availability, cost,reactivity and high charge density is 1,3-dimethylaminopropylchloride.This material is normally furnished commercially as a solidhydrochloride of the formula: ##STR7##

The solid hydrochloride is initially treated with a base such as sodiumhydroxide to convert it to a liquid form. The resulting liquid isinsoluble in water. In a first procedure the water-insoluble, liquidmonomer is converted to water soluble prepolymer having the structure offormula II by heating the insoluble monomer in alcohol, preferably atreflux and evaporating to dryness to form a low molecular weightprepolymer solid which is soluble in water. This polymer can bedissolved in water and further polymerized to a solid product having amolecular weight above 30,000 and an intrinsic viscosity in 0.4OMaqueous KBr of above 0.15 dl/g, typically 0.24 dl/g.

In an alternative procedure, the insoluble monomer can be dispersed inwater by means of 0.001 to 30% by weight of a nonionic surfactant,suitably difunctional block-polymers terminating in primary alcoholgroups with molecular weights ranging from 1,000 to over 15,000 such asa polyoxyalkylene derivative of propylene glycol or polyvinyl alcohol.Suitable materials are Pluronic F.68, P.85, or 6.62 (Wyandotte ChemicalsCorp.).

The branch or star polymers can be formed by indirect or directpolymerization procedures. In a first procedure a stoichiometric amountof AB monomer can be added based on the amount of D to form an adduct ofAB with each D group. Homopolymerization can then proceed forming radialAB polymeric chains from each functional site.

In another procedure the AB monomer is added to the branch polymersubstrate or star nucleus and copolymerized directly to form the highcharge density product radiating polyquaternary sections. In a furtherprocedure, the AB monomer is prepolymerized and the homopolymer isattached to the D sites or the D-AB adduct sites of the branch or starnucleus.

In the case of substrate branch polymers or central star monomers havingresidual reactivity, it is possible to form a water soluble comb-polymeror star polymer intermediate which can be coated onto a substrate orimpregnated into a carrier and then immobilized by heating the productto render the polymer water insoluble. For example,polyvinylbenzylchloride comb polymer froms an insolubilized structurewhen heated. Apparently there are unreacted chloromethyl groups presentwhich react with benzene rings on other polymer chains to formcross-links by an alkylation mechanism. This will be very useful inmanufacturing photocopy papers in which the paper can be impregnatedfrom aqueous solution and then heated to convert the polyelectrolyte toa water insoluble form.

The polyelectrolytes of this invention are in each case terminated witha reactive Z-- or (CH₃)₂ N-- group. The water soluble polymericintermediates can be further reacted with polyfunctional compounds ofthe formula: ##STR8## where D is defined above, R⁵ is an organic group,and m is a number from 0 to 2, to form cross-linked or gelled, waterinsoluble products.

In the case of a homopolymer, D can be either tertiary amine or chloro,bromo or iodo. In the case of a star or branch polymer, D is selected tobe reactive with the end group of the chain. Thus, a chloro substitutedcentral star monomer or polymer will form chloro terminated chains.Therefore, a diamine would be selected for cross-linking.

Exemplary polyamines are selected from compounds of the formula:##STR9## where R⁶ and R⁷ are hydrocarbon radicals such as alkyl, aryl oralkenyl preferably containing 1 to 10 carbon atoms or R⁶ and R⁷ may bejoined into a single hydrocarbon radical. R⁵ is a divalent organicradical containing at least 2 carbon atoms such as alkylene, arylene,cycloalkylene, alkenylene, aralkylene, polyoxyalkylene orpolythioalkylene. R⁵ may contain 3-100 carbon atoms and may be ofprepolymer length.

Exemplary ditertiary aliphatic amines are N, N, N',N'tetramethylhexamethylene diamine or tetramethyldecamethylene diamine.Heterocyclic compounds can also be utilized in which case R⁶ and R⁷ maybe combined. Examples of such ditertiary amino compounds are1,2-bis-(4-pyridyl)-ethane or 1,2-bis-(4-pyridyl)-ethene. Otherditertiary nitrogen derivatives may be formed from heterocycliccompounds such as picoline, quinoline, acridine, phenanthridine,phenanthroline, or N-alkyl piperidine, pyrrolidone or pyrrole.

Dihalo cross-linking agents may be selected from those of the formula:

    Z--R.sup.5 --Z

where R⁵ is as defined above. Examples of specific compounds are1,3-dibromopropane, 1,4-dibromobutane, 1,4-dibromobutene,1,5-dibromopentane, 1-10-dibromodecane, 1,6-dichlorohexane anddibromodimethylbenzene.

The polyelectrolytes of the invention exhibit bacteriostatic as well asbacteriocidal activity when tested by standard clinical proceduresagainst gram positive and gram negative bacteria cultures. Thesolubility of the high molecular weight polyelectrolytes, therefore,permits formation of a solution which can be topically applied totraumatic skin areas of the subject such as burns, abrasions or cuts.

Particularly useful compositions can be formed by the addition of asupplemental water soluble film former such as polyvinyl alcohol orpolyvinyl pyrrolidone. The polyelectrolyte may impart elastomericproperties to the final film. The solution is applied to a wound and onevaporation of the water an elastic membrane film is cast. The film isreadily removed by application of water. The solution is also veryeffectively applied to tissue as a spray to achieve a lasting adherentbacteriostatic film which will expand and contract with the movement ofthe tissue. This is very important in the need to exclude air and retainmoisture when dressing burns. Furthermore, the film simultaneouslyexhibits antiseptic, astringent and coagulant activity. The solution canalso be utilized to impregnate gauze materials to form an antiseptic,coagulant, germicidal dressing material.

The polyelectrolytes of this invention can also be dispersed in a waterinsoluble binder. The polyelectrolyte may be compounded and dispersedinto a water insoluble binder such as a polyester, polyamide or vinylresin or the binder may be formed in the presence of thepolyelectrolyte. For example, the polyelectrolyte can be compounded withco-reactive, water soluble, polymers such as polyvinyl alcohol andpolyacrylic acid. The solution may be cast and then heated to form estercross-links between the OH groups of the polyvinyl alcohol and COOHgroups of the polyacrylic acid. The final film is water swellable butwater insoluble.

The polyelectrolytes of this invention may also be reacted with anionicpolymers or salts thereof such as polystyrene sulfonates, polyacrylatesand the like and particularly with heparin or its alkali or ammoniumsalts to form inonically-linked, polymeric salts.

The nature of the cross-links is due to an ionic bond between negativegroups on the anionic polymer and the quaternary nitrogen on thepolyelectrolyte. The polymeric salts which contain heparin would providenon-thrombogenic surfaces.

Film or membranes can be formed by casting a solution of the copolymersalt and evaporating the solvent. The surfaces of membranes, tubes,catheters, valves, prosthetic veins, etc., can be coated with solutionsof the heparin, copolymer salt and the solvent removed, suitably byvacuum drying to deposit a non-thrombogenic coating. The copolymer saltis compatible with numerous substrates such as Tygon (polyvinyl) Teflon(polytetrafluoroethylene), Dacron (polyester), silicone resins, glass,polystyrene, and polyurethane.

The characteristics of the film or membrane depend on the particularpolyelectrolyte and anionic polymer utilized. The membranes, films ormolded articles may be utilized in water desalination, prosthetic bodyimplants and battery separators.

Polymeric analogs of organic charge transfer complexes can be preparedwhich exhibit high electrical conductivity. For example, the cationicpolyelectrolytes can be combined with 7,7,8,8-tetracyanoquinodimethane(TCNQ) to form salts having high conductivity. The mechanism ofelectronic transport or pseudometallic behavior of the polymeric saltsis not well understood. The salts exhibit high electrical conductivitiesin the presence of lithium TCNQ. On addition of neutral TCNQ theresistivity of the product is dramatically lowered probably caused byincreased electron delocalization. The polyelectrolytes and the saltswith charge transfer complexes thereof will find use as totally organicconductive materials.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following examples illustrate preparation of homopolymers from ABmonomers.

EXAMPLE 1

12.1 grams of 1,3-dimethylaminopropylchloride (DMAP Cl) was added to 100ml of absolute alcohol to form a one molar solution of the monomer. Thesolution was then refluxed under nitrogen for four hours. Afterrefluxing, the alcohol solvent was removed by vacuum evaporation. Twelvegrams of a prepolymer was obtained which had an intrinsic viscosity ofabout 0.03 in 0.4 M KBr. Six grams of the low molecular weightprepolymer obtained was then dissolved in 4 ml of water. The solutionwas heated for 41/2 hours at 95° C. under a nitrogen atmosphere. A solidreaction product was isolated which had an intrinsic viscosity of 0.21and is a solid homopolymer having a molecular weight above 20,000.

EXAMPLE 2

26 g of DMAP Cl was reacted with mechanical stirring in 8 ml of H₂ Ounder N₂ at 100° C. for four hours. Upon freeze drying and subsequentvacuum drying at 60° C. for 24 hours, 18 g of water soluble polymer wasobtained (69.2% yield) [η] = 0.24 in 0.4 M KBr.

EXAMPLE 3

Following the procedure of Example 2, 26 g of DMAP Cl was reacted with 8ml H₂ O in air at 100° C. for four hours. 16 gm of water soluble polymerwas obtained (61.5%) [η] = 0.146 in 0.4 M KBr.

EXAMPLE 4

Following the procedure of Example 2, 26 gm ofdimethylaminopropylchloride was reacted in 8 ml H₂ O under O₂ at 100° C.for 4 hours. A small amount of white ppt was obtained. The white ppt wasinsoluble in H₂ O (about 1 gm of insoluble polymer ˜ 3.9%). The yield ofwater soluble polymer was 65.4% (19 gm) [η] = 0.098.

EXAMPLE 5

The homopolymer prepared in accord with the procedure in Example 1 wastested as a flocculating agent by a technique described by D. Casson andA. Rembaum POLYMER LETTERS 8, 773 (1970). The optimum polymer dosage forthe homopolymer of Example 1 for the flocculation of a clay suspensionin accordance with the method described was 20 μg/l. This compares to acommercial polyelectrolyte, poly (2-methyl-5-vinylpyridiniumchloride)having an approximate molecular weight of 10⁶, which required a dosageof 60 μg/l when tested under identical conditions.

The homopolymers branch and star polymers of this invention can beutilized to form conductive hydrogels having unusually highconductivity. The hydrogels are prepared by reacting a polymer of thisinvention with a gel forming polymer such as polyvinyl alcohol,polyacrylic acid, alginic acids and polyethers. Cross-linked hydrogelscan be prepared from aqueous solutions of a mixture of polyvinyl alcoholand polyacrylic acid or polyhydroxyethylmethacrylate. The hydrogels canbe comprised of from 20 to 95 weight percent of the gel former with theremainder being the polyelectrolyte of this invention.

EXAMPLE 6

To a solution of 4 grams of polyvinyl alcohol in 200 cc of water wasadded a solution of 1 gram of homopolymer of Example 1 in 10 cc ofwater. The two solutions were stirred until a homogenous viscousmaterial was obtained. The mixed solution after casting on a glass plateyielded an elastic film. At 20 percent humidity, the surface resistivityof the film was found to be 4.9 × 10⁵ ohms/cm².

EXAMPLE 7

An insoluble cross-linked hydrogel was prepared from an aqueous solutioncontaining 40 weight percent polyvinylalcohol, 40 weight percentpolyacrylic acid, and 20 weight percent of the homopolymer of Example 1in water. A film was cast from the solution. The cast film was thencross-linked by heating at 100° C. for 10 minutes. The surfaceresistivity at 20 percent humidity of the cross-linked film was 2×10⁴ohms/cm².

In the preparation of a star polymer the polyamine or polyhalide isfirst dissolved in a highly polar solvent such as dimethylformamide(DMF) dimethyl-sulfoxide (DMSO), methanol and their mixtures with water.The AB monomer is then added to this solution in a substantialstoichiometric excess and heated to a temperature from 40° C. to 100° C.The star polymer is recovered by evaporating solvent. Specific examplesfollow.

EXAMPLE 8

An amine of formula V where p is 6 was synthesized by reacting 0.10 moleof hexamethylene-1, 6-diisocyanate added dropwise with stirring to 0.2moles of 1,3-bis-(dimethylamino)-2-propanol in a flask cooled in an icebath. Both the reactants were freshly distilled under vacuum before use.The reaction mixture was then allowed to warm gradually to roomtemperature and stirring continued for several hours. The viscous liquidwas diluted with toluene and the product separated from the latter beether extraction of the toluene. The structure of the amine wasconfirmed by means of NMR and IR spectra.

EXAMPLE 9

A tetrafunctional tertiary amine of the formula: ##STR10## wassynthesized by adding 0.1 mole of toluene-2, 4-diisocyanate drop-wisewith stirring to 0.2 mole of 1,3-bis-(dimethylamino)-2-propanol cooledin an ice bath. Both of these reactants were freshly distilled undervacuum before use. After allowing them to warm to room temperature, thereaction mixture solidified. The solid cake formed was broken up andwashed thoroughly with benzene and then dried in a vacuum oven at 40° C.The structure of the tetrafunctional amine was confirmed by NMR and IRspectra.

EXAMPLE 10

Four solutions were prepared in 4:1 by volume DMF-H₂ O containing (A)the compound of Example 8, (B) the compound of Example 9, (C)2,4,6-tri-(chloromethyl)-mesitylene and (D)1,2,4,5-tetra-(chloromethyl)-benzene. 50 cc portions of the solutionswere added to DMAP Cl is the following proportions:

                  Table I                                                         ______________________________________                                               Weight of        Weight of                                             Solution                                                                             Compound, grams  DMAP Cl, grams                                        ______________________________________                                        A      0.044            12.6                                                  B      0.034            12.6                                                  C      0.050            12.6                                                  D      0.060            12.6                                                  ______________________________________                                    

The mixtures were heated at 54° C. for seven days. A small amount ofwater was then added to dissolve some insoluble material formed duringthe reaction period. All the samples were rotary evaporated to drynessand thoroughly washed with acetone and dried in a vacuum oven at 40° C.for four days. The yield of all samples after drying was 100 percent.The intrinsic viscosities of the materials determined in 0.4 M KBraqueous solution were as follows:

                  Table II                                                        ______________________________________                                        Sample                 [m], 0.4 M KBr                                         ______________________________________                                        A                      0.15                                                   B                      0.14                                                   C                      0.18                                                   D                      0.15                                                   ______________________________________                                    

To confirm the presence of the star polymer, one gram of Sample D wasdissolved in methanol. 0.05 grams of 1,4-dibromobutene was added and themixture was heated at 60° C. for ten minutes. A gel was formed which wasinsoluble in water as well as common organic solvents. The formation ofthe gel by cross-linking the tertiary amine terminated branches with thereactive bromo groups served as evidence of the presence of the brancheson the Sample D material.

EXAMPLE 11

Of the star polyelectrolytes of Example 10, A-D were tested asflocculation agents for clay suspensions in accordance with theprocedure of Example 5. The optimum dosage of the star polyelectrolyteswas 20 μg/l as compared to 60 μg/l for the commercial material.

The comb-like structure of the branched polyelectrolytes of thisinvention also forms a material having a plurality of multiple chargedbranch side chains. The high concentration of charges provides superiorflocculation action for colloidal impurities in water purification.Higher molecular weight materials can be more readily achieved bybranching than by linear polymerization. Four 25,000 molecular weightlinked chains are the equivalent of a single linear 100,000 molecularweight polymer.

In the branch polymerization the first step is addition of a single ABgroup to the polymeric backbone as illustrated below withpolyvinylbenzylchloride: ##STR11##

The Cl atom on the adduct is then available for chain propagation with afurther molecule of DMPA Cl to form a polymeric chain of the comb-likestructure.

When a tertiary nitrogen is pendant from the polymer backbone, such asin polyvinyl pyridine, the AB monomer adduct will have a structure ofthe formula: ##STR12##

Similarly polydimethylaminoethylmethacrylate will form adducts of theformula: ##STR13##

Further AB addition will extend the branch chain which will terminate ina dimethylamino group.

In the procedure in which the AB monomer adduct is formed initially, itis preferred that the equivalent ratio of AB monomer to polymer be 1:1with respect to the A or B reactive functionality of the polymer. Theadduct formation is preferably conducted at ambient temperature in ahighly polar solvent such as DMF-methanol.

The adduct is precipitated in acetone and dried. Although neither thesubstrate polymer or the AB monomer are soluble in water, the adduct iswater soluble. The dried adduct is then dissolved in water andadditional monomer added. The soluble adduct polymer is found to act asa dispersing agent for the added AB monomer.

It is again preferred to conduct the linear AB polymerization in absenceof oxygen which favors higher molecular weight products. Heating thereaction mixture to a temperature between 80° C. - 110° C. acceleratesthe reaction. The reaction is complete when a viscous solution or solidcake is formed. The mixture is freeze dried and water removed.

The two-stage reaction can also be conducted in bulk in the presence ofexcess AB monomer. The excess monomer will act as a solvent or diluentfor the adduct. In the first step conducted at ambient, the adduct willform utilizing one unit of AB monomer per unit of reactive group on thepolymer. The temperature is then raised and head-to-tail ABpolymerization will proceed without the need to add more monomer.

Another technique is the attachment of preformed linear polymeric chainsof AB monomer to the substrate polymer. This reaction can be conductedin highly polar solvent such as DMF-methanol and at room temperature.

The reaction must be carefully conducted in order to obtain a watersoluble branched polymer. If the reaction mixture of substrate polymerin DMF-methanol contains excess AB monomer and is heated to atemperature above 80° C. an insoluble product is formed. However, awater soluble branched polymer is formed if this reaction is conductedin water or methanol.

The linear polymerization in the two-stage process must be carried outin the presence of water or methanol to assure a water soluble productexcept in the case of a bulk reaction.

EXAMPLE 12

31.g of polyvinylbenzylchloride were added to a 100 cc flask togetherwith 26 grams of DMAP Cl. The reaction mixture was stirred at roomtemperature for 30 minutes, until the adduct formed as a precipitatewhich was then diluted with 60 ml of water. The solution formed was thenheated in the presence of nitrogen for two hours at 100° C., duringwhich the linear polymerization of the branch chains occurred due to theexcess of the monomeric material present. The solution was then furtherdiluted with 250 cc of water and freeze dried. The dried solid endproduct was soluble in water, methanol and 0.1 M sodium nitrate. The dryproduct, on heating at 60° C. for two days, became partially insolublein water. Heating at 100° C. for the same period rendered the productcompletely insoluble in water.

The intrinsic Viscosity of the formed product was found to be 0.38 in0.4 M KBr. Gel permeation chromatography showed a single peak whichindicated only a single species was present which was assumed to be thebranched polyelectrolyte. Furthermore, when the same reaction wascarried out with dimethylaminopropylchloride alone under identicalconditions the intrinsic viscosity did not exceed 0.2.

When the reaction was carried out in absence of nitrogen gas only lowintrinsic viscosity (0.1) products were obtained.

EXAMPLE 13

Six grams of poly 4-vinylpyridine was dissolved in 60 ml of DMF. 8 gramsof dimethylamino-n-propylchloride were added to the solution. Themixture was then heated at 95° C. for 18 hours under a nitrogenatmosphere.

The adduct was isolated as a low molecular weight polymer in an amountof 13.8 grams. The adduct was soluble in methanol, water and 0.1 Msodium nitrate and insoluble in acetone, DMF, and 0.4 M KBr. Theintrinsic viscosity in 0.1 M NaNO₃ was 0.233.

EXAMPLE 14

Five grams of the product of Example 13 was dissolved in 16 ml of water.To this solution was then added 26 grams ofdimethylamino-n-propylchloride. The mixture was heated to 100° C. forfour hours under a nitrogen atmosphere. A green solution wasprecipitated in acetone and the product dried in a vacuum oven at 30° C.overnight. 30.2 grams of a product was obtained. The product was solublein 0.4 M KBr, H₂ O, MeOH and 0.1 M sodium nitrate. The intrinsicviscosity in 0.1 M sodium nitrate was 0.319.

EXAMPLE 15

An AB homopolymer was prepared having an intrinsic viscosity of 0.024and was synthesized in accord with the method set forth in Example 2above. 2.5 grams of the homopolymer of dimethylaminopropylchloride weredissolved in 30 ml methanol to which was then added 32 ml of DMF. Asecond separate solution was prepared containing 0.20 grams ofpolyvinylbenzylchloride having an average molecular weight of 40,000dissolved in 2.2 ml of DMF. 2 ml of methanol were added to the secondsolution. The second solution of the backbone polymer was added to thehomopolymer solution drop-wise with mixing. The mixture was allowed toreact at room temperature for 24 hours. The solvent was then removed byvacuum evaporation. The resulting polymer weighed 2.7 grams and was notsoluble in H₂ O, methanol and DMF.

EXAMPLE 16

The branched polyelectrolyte formed in Example 14 above was utilized ina flocculation procedure as set forth in Example 5 above. An optimumdosage of 15 μg/l of the polyelectrolyte was determined for theflocculation of a clay suspension.

EXAMPLE 17

An insoluble cross-linked hydrogel film was prepared from an aqueoussolution containing 40 weight percent polyvinylalcohol, 40 weightpercent acrylic acid, and 20 weight percent of the branchpolyelectrolyte of Example 14. Cross-linking was achieved by heating acast film of the material at 100° C. for 10 minutes. The surfaceresistivity at 20 percent humidity for the film was 4.4 × 10⁵ ohms persquare.

EXAMPLE 18

A typical starch barrier coated raw paper stock was coated with acomposition consisting of 50 parts of clay conventionally utilized formaking reproduction paper, 25 parts of polyvinylalcohol and 25 parts ofthe branch polyelectrolyte of Example 14 on a basis of 3 pounds of thecomposition per 3,000 square feet of paper surface. The surfaceresistivity of the coated paper at 10% relative humidity was found to be10⁹ ohms/square.

EXAMPLE 19

0.22 gm of polyethylene imine (.005 mole) were mixed with 30.35 gm ofDMAP Cl (0.25 mole). Ten ml of water were added and the mixture heatedfor two hours at 100° C. An additional 10 ml of water were added and themixture heated to 100° C. for another hour. A further 10 ml of waterwere added and heating continued for an additional 17 hours. Theisolated branch polymer had an intrinsic viscosity of 0.15 dl/g.

High purity DMAP Cl monomer was prepared according to the followingprocedure.

EXAMPLE 20

DMAP Cl monomer was isolated from its hydrochloride salt by reactionwith NaOH. 100 g (0.633 mole) of 3-dimethylamino-n-propyl chloridehydrochloride was dissolved in the minimum quantity of water, cooled inan ice bath and 200 ml of 20% NaOH solution added dropwise with vigorousstirring. The monomer was then extracted with several small portions ofether. The ether extracts were combined, washed twice with water andthen dried over anhydrous magnesium sulfate. After a drying period of 12hours, the ether solution was filtered and then rotary evaporated. Themonomer, together with a small quantity of remaining ether, was finallyvacuum distilled. The fraction distilling between 22° C. and 25° C., at5 mm Hg pressure, was collected and stored at 0° C. until required. BothNMR and IR spectra confirmed the structure and purity of the monomerprepared as described above.

The monomer was allowed to polymerize at 41° C. for five days in varioussolvent systems. The initial monomer concentration was kept constant at1.0 molar. The results are summarized in Table III.

                  TABLE III                                                       ______________________________________                                        Effect of Solvent                                                                                              (η) in 0.4M                              Solvent    Volume Ratio                                                                              % Yield   aq. KBr dl/g                                 ______________________________________                                        DMF*/MeOH  (1:1)       46        0.051                                        DMF/MeOH   (1:2)       36        0.047                                        DMF/MeOH   (1:3)       30        0.024                                        DMF/H.sub.2 O                                                                            (4:1)       100       0.092                                        DMSO**/H.sub.2 O                                                                         (4:1)       100       0.064                                        DMSO/MeOH  (4:1)       101       0.014                                        CHCl.sub.3             90        0.050                                        CH.sub.3 CN            81        0.053                                        ______________________________________                                          *Dimethylformamide                                                           **Dimethylsulfoxide                                                      

Table III shows that for the solvents tested the highest intrinsicviscosity was achieved in the DMF/H₂ O system. The monomer was thereforeallowed to polymerize at various temperatures using 4:1 DMF/H₂ O assolvent and an initial monomer concentration of 1.0 mole/l. The reactionwas allowed to continue until titration of unreacted end groupsindicated that the polymerization was complete. The results aresummarized in Table IV.

                  TABLE IV                                                        ______________________________________                                        Effect of Temperature                                                         Temperature ° C.                                                                   % Yield   (η) in 0.4M aq. KBr dl/g                            ______________________________________                                        41          114       0.092                                                   54          100       0.100                                                   68          111       0.112                                                   82          101       0.089                                                   96          107       0.073                                                   ______________________________________                                    

The yields over 100% are due to insufficient drying time. For thissolvent system, the molecular weight decreases if the polymerization iscarried out at a temperature above about 75° C.

The monomer was allowed to polymerize in either 4:1 DMF/H₂ O at 54° C.,using various initial monomer concentrations and a 48 hour reactiontime. The results are shown in Table V.

                  TABLE V                                                         ______________________________________                                        Effect of Initial Monomer Concentration                                                Initial Monomer        (η) in 0.4M aq.                           Solvent  Conc. (mole/l)                                                                             % Yield   KBr dl/g                                      ______________________________________                                        DMF/H.sub.2 O                                                                          0.5          98        0.033                                         DMF/H.sub.2 O                                                                          1.0          99        0.126                                         DMF/H.sub.2 O                                                                          1.5          100       0.142                                         DMF/H.sub.2 O                                                                          2.0          86        0.194                                         DMF/H.sub.2 O                                                                          2.5          91        0.175                                         DMF/H.sub.2 O                                                                          3.0          100       0.162                                         DMF/H.sub.2 O                                                                          3.5          100       0.164                                         DMSO/H.sub.2 O                                                                         1.0          100       0.064                                         DMSO/H.sub.2 O                                                                         1.5          100       0.102                                         DMSO/H.sub.2 O                                                                         2.0          100       0.129                                         Bulk     --           25        0.070                                         ______________________________________                                    

Tables III, IV and V indicate that for relatively high molecular weightthe optimum solvent system is the DMF water mixture at temperatures inthe range of 50° to 80° C. and at a concentration of 2 to 3.5 moles/l.The insolubility of the final polymer in DMF water mixtures could be areason for the difficulty in achieving intrinsic viscosities higher than0.2 dl/g in 0.4M KBr solutions. The polymerization was thereforeinvestigated in pure water in which the polymer is miscible in allproportions.

The 3,3-ionene chloride (AB polymer) was obtained by heating a stirredsuspension of AB monomer in water. Table VI, below, illustrates theeffects of air, oxygen and nitrogen on the yield and intrinsic viscosityof the polymer formed in the aqueous system.

                  TABLE VI                                                        ______________________________________                                        Polymerization of AB monomer in water                                         in presence and absence of air                                                                          Time of                                                                              Con-                                         Temp. Experim.  Monomer   Reaction                                                                             version                                                                             (η) in                             ° C.                                                                         Condition Conc. m/l hrs.   %     0.4M KBr                               ______________________________________                                        100°                                                                         Air       5.96      4      62    0.146                                  100°                                                                         Oxygen    5.96      4      66    0.098                                  100°                                                                         Nitrogen  5.96      4      70    0.208                                  100°                                                                         Vacuum    5.96      50     100   0.224                                  100°                                                                         Nitrogen  5.96      50     100   0.223                                  ______________________________________                                    

The aqueous polymerization system (Table VI) thus offers a convenienttechnique for the synthesis of 3,3-ionene chloride with viscositieshigher than those achieved in other solvents provided the process iscarried out in absence of air and at high monomer concentration.Additional studies of monomer concentration and reaction time confirmedthe above conclusion as illustrated in Table VII, which follows.

                  TABLE VII                                                       ______________________________________                                        Polymerization of AB monomer in water                                         Effect of reaction time and monomer concentration at 100° C.           ______________________________________                                        Monomer   Reaction                   (η) in                               Concentration                                                                           Time     Exp.      %       0.4M KBr                                 m/l       hrs.     Conditions                                                                              Conversion                                                                            dl/g                                     ______________________________________                                        5.96      4        under N.sub.2                                                                            70     0.208                                    5.96      50       "         100     0.223                                    4.87      8        "          90     0.199                                    4.46      8        "          90     0.189                                    4.12      8        "         --      0.140                                    6.69      50       Vacuum    100     0.199                                    5.96      50       "         100     0.223                                    5.96      50       under N.sub.2                                                                           100     0.223                                    5.96      148      vacuum    100     0.240                                    5.96      384      vacuum    100     0.230                                    5.54      50       "         100     0.210                                    4.87      50       "         100     0.174                                    4.46      50       "         100     0.162                                    4.12      50       "         100     0.145                                    ______________________________________                                    

The aqueous polymerization system can also be carried out at highertemperatures than the DMF/H₂ O system. At higher temperatures in thepresence of DMF, side reactions occur resulting in a lower intrinsicviscosity. Higher molecular weights are favored at higher concentrationin water. The initial monomer concentration is at least 4 mole/l andpreferably at least 6 mole/l. An even higher molecular weight wasobtained by a multistage polymerization procedure in which the initialmonomer concentration is at least 4 mole/l and polymerization proceedsfor a first period to less than 100% but more than 50% conversion topolymer. The polymerization mixture is then diluted by diluting themonomer concentration as initially determined by at least 10% andpolymerization continued to completion.

A very high molecular weight polymer was obtained by the followingprocedure.

EXAMPLE 21

DMAP Cl monomer (52g) and water (16 ml) were combined to form a 7.22molar mixture. The mixture was heated at 100° C. in the presence ofnitrogen for four hours. A solid material formed at the end of 4 hours.Another 16 ml of H₂ O was then added (dilution to 5.9 molarity on aninitial basis) and the heating was continued for another 20 hours.

The 3,3-ionene chloride was then isolated. The intrinsic viscosity in0.4M KBr was found to be equal to 0.25 dl/g which corresponds to amolecular weight of 63,000 as determined by the technique discussedbelow.

When this polymer is compared to the highest molecular weight polymershown in Table VII, it is evident that reaction time has been decreasedfrom 148 hours to 24 hours and the molecular weight of the product ishigher at the shorter reaction time.

The molecular weights reported by the present inventors have beendetermined from the intrinsic viscosity molecular weight relationship inaqueous 0.4M KBr by means of light scattering and can be expressedapproximately by:

    [η] = (2.94 × 10.sup..sup.-4)M.sup.0.61

further details of the procedure are discussed by Casson and Rembaum,Macromolecules 5, 75 Jan.-Feb. 1972.

Reaction rates, for the homoploymerization of the DMAP Cl monomer, weremeasured by means of NMR spectra, determined at 60 or 220 megacycles orby titration of unreacted tertiary amine end groups. An aliquot of thereaction mixture was added to excess dilute hydrochloric acid and theunreacted acid titrated potentiometrically with dilute sodium hydroxidesolution.

The rate of polymerization was followed by the previously describedtitration technique or by monitoring the NMR resonance peaks, either dueto decreasing concentration of the ##STR14## protons or increasingconcentration of ##STR15## as a function of time. The validity of thisprocedure is substantiated by a careful analysis of high resolution 220mc NMR spectra of the monomer and polymer; however, the actual rateswere established using a 60 mc NMR spectrometer. The spectral changesoccurring with time were determined. The rates of polymerizationmeasured by means of the NMR technique agreed with those obtained bypotentiometric titration of the chloride ion within ±10%. The kineticresults reflect the increase in rate at room temperature as thedielectric constant of the solvent increases. The same effect is shownat 55° C.

The molecular weight of the polymer increased with time of conversion asexpected from a step growth polymerization system. The intrinsicviscosities determined in 0.4M aq. KBr as a function of polymerizationtime are shown in Table VIII.

                  TABLE VIII                                                      ______________________________________                                        Intrinsic viscosities of AB polymer isolated                                  from separate batches of 1 molar AB monomer and                               polymerized at 54° C in DMF/H.sub.2 O (4:1)                            as a function of time                                                         ______________________________________                                        Time          (η) in 0.4M aq. KBr                                         (hrs)         dl/g                                                            ______________________________________                                        16.0          0.062                                                           21.5          0.097                                                           47.2          0.122                                                           71.5          0.117                                                           383.5         0.101                                                           ______________________________________                                    

The examination of Tables V and VIII indicates that relatively longreaction times lead to a decrease in intrinsic viscosity. In order toascertain whether this decrease was due to occurrence of degradation,the polymers were kept at elevated temperatures in aqueous solutions andthe relative viscosity of isolated samples was determined as a functionof heating time. The data show that the polymer degrades slowly inwater, much faster in presence of NaOH but is stabilized in presence ofHCl.

The high crystallinity of different ionene bromides was established bythe examination of X-ray diffraction patterns using CuKα radiation.Similar results were obtained with 3,3-ionene chloride. The X-raydiffraction patterns show that the high crystallinity persists in lowand high molecular weight polymers and that the same is also true for3,3-ionene perchlorate and 3,3-ionene triiodide.

A comparison of specific reduced viscosity of 3,3 and 6,6-ionenechloride as a function of ionic strength indicates that an ionenecontaining a large number of positive charges in its chain undergoesmore extensive coiling with increasing ionic strength than thecorresponding ionene with comparatively low numbers of positive charges.This is evidenced by comparing the [η]_(sp/c) of 3,3-ionene chloridewith that of 6,6-ionene chloride as a function of KBr concentration. Thecomparison also confirms the effect of decreased viscosity in KBr ascompared with KCl solutions.

The intrinsic viscosities of polymer samples isolated from separatebatches of 5.91 molar DMAP Cl monomer polymerized at 100° C. in waterare shown as a function of time in the following table:

                  TABLE IX                                                        ______________________________________                                                               Intrinsic Viscosity                                    Time, hrs.             in 0.4M KBr, dl/g                                      ______________________________________                                        0.5                    0.051                                                  3.0                    0.131                                                  4.0                    0.158                                                  50.0                   0.210                                                  180.0                  0.230                                                  ______________________________________                                    

Again, the molecular weight increased with time of conversion asexpected from a step growth polymerization system.

The effectiveness of the polyelectrolytes as dewatering agents forsludge was determined according to the Buchner funnel test. The test wasconducted by adding an optimum amount of polyelectrolyte to apredetermined amount of sludge, placing the sludge on a sheet of 9 cmWhatman paper No. 4 within a Buchner funnel, applying a 24 inch vacuumto the funnel and measuring the volume of water collected over a timeinterval.

EXAMPLE 22

The optimum concentration of polyelectrolyte for dewatering wasteactivated sludge was first determined. The optimum amount of eachpolyelectrolyte was then added to a 500 ml sample of sluge containing 2%sludge solids, stirred at high velocity for 10 seconds, poured into theBuchner funnel and the vacuum activated. The results follow:

                  TABLE X                                                         ______________________________________                                                            Amount   Water,  Time,                                    Polyelectrolyte     mg/l     ml      sec.                                     ______________________________________                                        None                         72      120                                      Homopolymer (Ex. 1) 115      100     99                                       Tetraamine Star (Ex. 10A)                                                                         500      100     90                                       Polyethylene Imine Branch                                                     (Ex. 19)            400      100     85                                       Polyvinylbenzylchloride Branch                                                (Ex. 12)            200      100     52                                       ______________________________________                                    

EXAMPLE 23

200 ml samples of digested sludge containing 3.5% solids were subjectedto the procedure of Example 22. The results follow:

                  TABLE XI                                                        ______________________________________                                                            Amount   Water,  Time,                                    Polyelectrolyte     mg/l     ml      sec.                                     ______________________________________                                        None                         23      120                                      Tetraamine Star (Ex. 10A)                                                                         200      34      120                                      Polyethylene Imine Branch                                                     (Ex. 19)            200      49      120                                      Polyvinylbenzylchloride Branch                                                (Ex. 12)            200      60      120                                      ______________________________________                                    

It is apparent that the effectiveness of the polyelectrolytes asdewatering agents increases as the charge density and amount ofbranching increases from homopolymer to star to branch, comb-polymer.

It is to be realized that only preferred embodiments of the inventionhave been described and that numerous substitutions, alterations andmodifications may be made without departing from the spirit and scope ofthe invention as defined in the following claims.

What is claimed is:
 1. A conductive composition consisting essentiallyof a dispersion of 20 to 95 percent by weight of a water-soluble gelforming binder polymer selected from polyvinyl alcohol or polyvinylalcohol cross-linked to a water-insoluble and water-swellable form byreaction with a coreactive water-soluble polymer and a linear,water-soluble polyelectrolyte of the formula: ##STR16## where Z ischloro, bromo or iodo and n is an integer such that the intrinsicviscosity, n, as determined by light scattering in 0.4 KBr is at least0.2 dl/g as determined by the formula:

    n= (2.94 × 10 .sup..sup.-4) M.sup.0.61

where M is molecular weight.
 2. A composition according to claim 1 inwhich the water soluble binder polymer comprises polyvinyl alcohol.
 3. Acomposition according to claim 1 in which the polyelectrolyte is presentin an amount from 10-30 weight precent of the composition.
 4. Acomposition according to claim 3 further including up to 50 weightpercent of an inert filler.
 5. A composition according to claim 4 inwhich the filler is a reprographic paper grade of clay.
 6. A compositionaccording to claim 1 in which Z is chloro.
 7. A conductive compositionaccording to claim 1 in which the coreactive polymers are polyvinylalcohol and polyacrylic acid.